physical injuries of oral cavity

PHYSICAL INJURIES OF TEETH

Guided ByDr. Mayur Chaudhary

Submitted By Karamjeet Singh

BRUXISM Non functional contact of teeth

which may include grinding,

gnashing or clenching of teeth.

TYPES

1. Day Time Bruxism/ Diurnal Bruxism/ Awake Bruxism

Conscious or subconscious grinding of teeth usually during the day.

2. Night Time Bruxism/ Nocturnal Bruxism/ Sleep Bruxism

Autonomic teeth grinding with rhythmic & sustained jaw muscle contractions.

ETIOLOGY

1. Local factors.

2. Systemic factors.

3. Psychological factors.

4. Occupational factors.

LOCAL FACTORS

Include occlusal interference, high restoration or some irritating dental conditions.

A patient brux as a result of an unconscious attempt to establish a greater number of teeth in contact or to counteract the local irritating situation.

In children bruxism may be related to growth & development. Children brux because their top & bottom teeth

don’t fit together comfortably.

SYSTEMIC FACTORS

Include GI disturbances, subclinical nutritional deficiencies, allergies, or endocrine disturbances.

Genetics has also been seen to play an important role in the etiology of bruxism. Children of bruxing parents have an increased

incidence of bruxism.

PSYCHOLOGICAL FACTORS

Most common cause of bruxism. Anxiety, stress or tension. Suppresed anger or frustation. Aggressive, competitive or hyperactive

personality type. Mental disorders are also related to bruxism.

OCCUPATIONAL FACTORS

Occupations in which the work must be unusually precise, such as watchmakers are more prone to cause bruxism.

Athletes often develop bruxism.

CLINICAL FEATURES

Symptomatic effects of bruxism have been divided in to 5 major categories :

1. Effects on the dentition.2. Effects on the periodontium.3. Effects on the masticatory muscles.4. Effects on the temperomandibular joint.5. Headache.

EFFECTS ON THE DENTITION

Severe wearing or attrition of the teeth may occur. not only occlusally, but also interproximally.

EFFECTS ON THE PERIODONTIUM

Loss of the periodontal structures, resulting in loosening or drifting of teeth or even gingival recession with alveolar bone loss.

EFFECTS ON THE MASTICATORY MUSCLES

Hypertrophy of the masticatory muscles, particularly the masseter muscle.

May interfere with maintenance of the rest position, cause trismus & alter occlusion & the opening & closing pattern of the jaw.

EFFECTS ON THE TEMPEROMANDIBULAR JOINT

Pain present in the joints is usually dull & unilateral.

Crepitation and clicking within the joint. Restriction of the mandibular movements. Jaw deviations can be observed.

HEADACHE

Bruxism may give rise to facial pain & headache.

TREATMENT & PROGNOSIS

Underlying cause must be corrected.

Removable occlusal splints may be worn at night to immobilize the jaws or to guide the movement.

FRACTURES OF TEETH

CLINICAL FEATURES

AGE : May occur at any age. But children are more prone.

SEX : M > F SITE : 75 to 90 % of traumatized teeth are

maxillary teeth.

ELLIS’S CLASSIFICATION It divides all the traumatized anterior teeth in to nine classes.CLASS 1 : Simple fracture of the crown, involving little or no dentin.CLASS 2 : Extensive fracture of the crown, involving considerable

dentin but not the dental pulp.CLASS 3 : Extensive fracture of the crown, involving considerable

dentin & exposing the pulp.CLASS 4 : The traumatized tooth becomes non-vital, with or

without loss of crown structure.CLASS 5 : Teeth lost as result of trauma.CLASS 6 : Fracture of the root, with or without loss of crown

structure.CLASS 7 : Displacement of a tooth, with or without fracture of

crown or root.CLASS 8 : Fracture of the crown en masse & its replacement.CLASS 9 : Traumatic injuries to deciduous teeth.

Clinical manifestation, treatment and prognosis of the fractured tooth depend upon whether the dental pulp is pierced by the fracture and whether the crown or the root is involved.

CROWN FRACTURE WITHOUT PULP INVOLVEMENT

Vitality of the tooth is usually maintained. There may be mild pulp hyperemia even

when the overlying dentin is relatively thick. If the dentin is very thin, bacteria may

penetrate the dentinal tubules, infect the pulp & produce pulpitis.

Tooth may be sore & slightly loose but severe pain is usually absent.

CROWN FRACTURE INVOLVING PULP

Pulp exposure does not mean that death of the pulp will occur.

Exposure can be capped by calcium hydroxide & a dentinal bridge will form as a part of the healing reaction.

Pulpotomy or pulpectomy may often be necessary, however, since the pulp becomes infected almost immediately after the injury.

ROOT FRACTURE Uncommon in young children, since their roots are

not completely formed & the teeth have some resilience in their sockets.

Occurs mostly as horizontal fractures in the middle third of the root.

Most teeth become non vital immediately after the root fracture.

Some root fractures may heal by forming an inner layer of reparative dentin on the pulpal wall, or they may replace the hard tissue along the fracture line with granulation tissue that progresses to mature connective tissue.

CEMENTAL TEARS

Small fractures of cementum, usually as a result of sudden rotational forces.

Occurs if the trauma is not forceful enough to fracture the tooth.

Asymptomatic & not of any clinical significance.

Occasionally observed as incidental findings during histologic examination of periodontal tissue removed for other purposes.

HISTOLOGIC FEATURES

Healing in such cases may be of several types.

Most satisfactory form of healing is the union of the two fragments by calcified tissue & this is analogous to the healing of a bony fracture.

If the apposition between the two fragments is not close, the union is by connective tissue alone.

TOOTH ANKYLOSIS

AKA DENTOALVEOLAR ANKYLOSIS INFRAOCCLUSION SECONDARY RETENTION SUBMERGENCE REIMPACTION REINCLUSION

ANKYLOSIS means fusion of a joint.

Tooth ankylosis means fusion of the tooth to the alveolar bone.

Def: Cessation of eruption after emergence occuring from an anatomic fusion of tooth cementum or dentin to alveolar bone.

ETIOLOGY

Unknown. PREDISPOSING FACTORS

1. Trauma.

2. Injury.

3. Changes in local metabolism.

4. Chemical & thermal irritation.

5. Local failure of bone growth.

6. Abnormal pressure from the tongue.

7. Genetically decreased PDL gap.

CLINICAL FEATURES Ankylosed teeth appears

submerged because its roots don’t grow at the same rate as other teeth.

Malpositioning of the teeth on either side of it.

Super eruption of the opposing teeth in the opposite dental arch.

Growth of permanent teeth will be blocked by the ankylosed tooth because the roots will not disolve.

PERCUSSION An ankylosed teeth has a higher pitched or

dulled sound as compared to the more cushioned sound of a normal tooth.

RADIOGRAPHIC FEATURES

Loss of normal thin radiolucent line that represents the periodontal ligament.

Mild sclerosis of the bone & apparent blending of the bone with the tooth root.

HISTOLOGIC FEATURES

On microscopic examination, an area of root resorption continuous with the alveolar bone is seen which has been repaired by a calcified material, bone, or cementum.

Periodontal ligament is completely obliterated.

TREATMENT

No specific treatment for ankylosis. When an underlying permanent successor is

present, extraction of the ankylosed teeth is recommended.

PHYSICAL INJURIES OF BONE

TRAUMATIC CYST

Aka Solitary bone cyst. Hemorrhagic bone cyst. Extravasation cyst. Unicameral cyst. Simple bone cyst. Idiopathic cyst.

“ Benign, empty, or fluid- containing cavity within bone that is devoid of an epithelial lining ”

Since this cyst does not have a true epithelial lining its not considered as true cyst.

ETIOLOGY

Unknown & controversial Several theories have been proposed, but none

of them explains all of the clinical & pathologic feature of this disease.

Trauma- Haemorrhage Theory

Most accepted theory

According to this theory Trauma to the bone that is insufficient to

cause a fracture results in an intraosseous haematoma.

If the haematoma does not undergo organization & repair, it may liquify & result in a cystic defect.

OTHER THEORIES Origin from bone tumors that have undergone cystic

degenerations. A result of faulty calcium metabolism such as that

induced by parathyroid disease. Origin from necrosis of fatty marrows due to

ischemia. The end result of a low grade chronic infection. A result of osteoclasis resulting from a disturbed

circulation caused by trauma creating an unequal balance of osteoclasis & repair of bone.

Local disturbances in bone growth.

CLINICAL FEATURES

AGE : Most frequently between 10 & 20 years of age.

SEX :

M : F - 3 : 2 SITE : Mandible.

Usually asymptomatic & discovered when radiographs are taken for some other reason.

Swelling is occasionaly seen. When the cavity is opened surgically, it is found to contain either a straw coloured

fluid, shreds of necrotic blood clot, fragments of fibrous connective tissue,

or nothing.

RADIOGRAPHIC FEATURES

Smoothly outlined radiolucent area of variable size.

Interradicular scalloping of varying degrees is characteristic of this lesion.

Occasionally slight root resorption may be noted.

HISTOLOGIC FEATURES

A thin layer of loose & delicate connective tissue lining the cavity.

Soft tissue luminal surface contains a thin layer of fibrin.

TREATMENT

Surgical entry to initiate bleeding & stimulate healing.

Rarely second surgical procedure is required. If a large space is present bone chips are

used.

FOCAL OSTEOPOROTICBONE MARROW DEFECT

Lesions that are typically present as asymptomatic, focal radiolucencies in areas where hematopoeisis is normally seen.

- Angle of mandible & maxillary tuberosity.

PATHOGENESIS

Three theories have been proposed :

1. Marrow hyperplasia in response to increased demand for erythrocytes.

2. Abberent bone regeneration after tooth extraction.

3. Persistence of the fetal marrow.

CLINICAL FEATURES

SEX : 75 % of lesions occuring in women. SITE : 85 % in the posterior mandible.

most often in edentulous areas. Typically asymptomatic & detected as an

incidental finding on a radiographic examination.

RADIOGRAPHIC FEATURES Radiolucent area varying in size from several

millimeters to several centimeters in diameter. Poorly defined periphery

Indicative of lack of reactivity of adjacent bone.

Fine central trabeculation may be observed in IOPA.

HISTOLOGIC FEATURES Consists of normal red marrow &/or fatty

marrow. Small lymphoid aggregate may be found. Bone trabeculae included in the biopsy

specimen show no evidence of abnormal osteoblastic or osteoclastic activity.

TREATMENT

Because of nonspecific radiographic findings, diagnosis by an incisional biopsy is generally desirable.

Once the diagnosis has been established, no additional treatment is necessary.

EFFECTS OF ORTHODONTIC TOOTH MOVEMENT

Orthodontic tooth movement is possible because the periodontal tissues are responsive to the externally applied forces.

Bone under pressure responds by resorbing, where as the application of tension results in deposition of new bone.

Although moderate orthodontic forces usually results in bone remodeling & repair, excessive forces may produce necrosis of the periodontal ligament & adjacent alveolar bone.

Excessive orthodontic forces also increases the risk of apical root resorption.

TIPPING MOVEMENT

The initial reaction on the pressure side is a compression of the periodontal ligament, which, if excessive & prolonged, may result in ischemia with hyalinization and/or actual necrosis of tissue.

On the opposite side, under excessive force, there may be actual tearing of the periodontal fibers & small capillaries with hemorrhage into the area.

With the reasonable forces, the periodontal ligament on the tension side of the tooth demonstrates stretching & widening of the periodontal space.

EXTRUSIVE MOVEMENT

Extrusion of a tooth by an orthodontic appliance is similar to normal tooth eruption.

The tissue changes induced by this form of movement consist in deposition or apposition of new bone spicules at the alveolar crest & at the fundus of the alveolus arranged in a direction parallel to the direction of force.

DEPRESSIVE MOVEMENT The application of orthodontic force in such a

manner as to cause depression of a tooth results in tissue changes that are the opposite of those found during extrusion, or elongation.

Resorption of bone occurs at the apical area & around the alveolar margin.

New bone formation is actually minimal.

TISSUE REACTIONS DURING RETENTION PERIOD

During this period there is gradual reformation of the normal dense pattern of the alveolar bone by apposition of bone around the bony spicules until they meet, fuse, & gradually remodel.

The studies of oppenheim indicated that this reformation is slower around teeth held in position during the retention period by a retaining appliance as compared to teeth, which remained free during this time.

EFFECT OF DECIDUOUS TOOTH MOVEMENT UPON PERMANENT TOOTH GERMS

Studied by Breitner & Tischler in monkeys. They found that when a deciduous tooth was

moved, the associated permanent tooth germ followed this movement.